MITOCHONDRIAL MALATE-DEHYDROGENASES IN BRASSICA-NAPUS - ALTERED PROTEIN-PATTERNS IN DIFFERENT NUCLEAR MITOCHONDRIAL COMBINATIONS

Two-dimensional analyses of mitochondrial proteins of Brassica napus r evealed a set of differences in patterns of mitochondrial matrix prote ins isolated from different nuclear backgrounds. One of these varying proteins was identified as mitochondrial malate dehydrogenase (mMDH; E C 1.1.1.37) by homology analyses of the partial amino acid sequence. I mmunological detection identified additional mMDH subunits and detecte d different patterns of mMDH subunits in two distinct mitochondria typ es although they were isolated from plants with the same nuclear genot ype. These differences are also reflected in isozym patterns, whereas Southern analyses showed no alteration in genome structure. Therefore mitochondria type-specific mMDH modifications are possible.